May 24 - Japan's Tokyo Electric Power Company (TEPCO) announced Wednesday that an investigation into the Gena vessel (the safety envelope surrounding the reactor) inside the Fukushima Daiichi Nuclear Power Plant Unit 1 found that part of the foundation concrete supporting the reactor pressure vessel was damaged and the steel bar inside was exposed.  Tepco said it was likely caused by heat from dissolved fuel.  
Tepco said it was the first time that the foundations of units 1 to 4 at the Fukushima plant had been damaged.  In addition, multiple white lumps were found directly under the pressure vessel of the Reactor unit 1.  Tepco believes that if there is significant damage to the foundation, the pressure vessel is likely to fall.  
 
 
 
In order to investigate the situation of unit 1 at the Fukushima Daiichi Nuclear Power Plant, Tepco put an underwater robot in February 2022 to inspect the inside of the reactor containment vessel of Unit 1.  The robot photographed what could be "nuclear residue" and sediment inside the containment vessel.  The investigation was interrupted in March when the robot was damaged by water while operating.  Some media pointed out that since the serious nuclear leakage accident at the Fukushima Daiichi nuclear power plant in 2011, the Japanese government and Tepco have taken ineffective measures and many loopholes in handling the nuclear accident